Mass Air Flow Sensor
The mass air flow sensor (1) is placed in the stream of intake air. It measures the intake flow rate by measuring a part of the entire intake flow. The mass air flow sensor consists of a heater and temperature sensors detecting heat generated by the heater at its upstream and downstream.
The upstream and downstream temperature sensors detect the same temperature under windless conditions. When the wind blows, a temperature difference develops between the upstream and downstream temperature sensors. The amount of intake air is detected according to the temperature difference.